@article{54865,
author = {{Krenz, Marvin and Gerstmann, Uwe and Schmidt, Wolf Gero}},
issn = {{0031-9007}},
journal = {{Physical Review Letters}},
number = {{7}},
publisher = {{American Physical Society (APS)}},
title = {{{Defect-Assisted Exciton Transfer across the Tetracene-Si(111):H Interface}}},
doi = {{10.1103/physrevlett.132.076201}},
volume = {{132}},
year = {{2024}},
}
@article{49634,
author = {{Ruiz Alvarado, Isaac Azahel and Zare Pour, Mohammad Amin and Hannappel, Thomas and Schmidt, Wolf Gero}},
issn = {{2469-9950}},
journal = {{Physical Review B}},
number = {{4}},
publisher = {{American Physical Society (APS)}},
title = {{{Structural fingerprints in the reflectance anisotropy of AlInP(001)}}},
doi = {{10.1103/physrevb.108.045410}},
volume = {{108}},
year = {{2023}},
}
@article{54852,
abstract = {{The crystal family of potassium titanyl phosphate (KTiOPO4) is a promising material group for applications in quantum and nonlinear optics. The fabrication of low-loss optical waveguides, as well as high-grade periodically poled ferroelectric domain structures, requires a profound understanding of the material properties and crystal structure. In this regard, Raman spectroscopy offers the possibility to study and visualize domain structures, strain, defects, and the local stoichiometry, which are all factors impacting device performance. However, the accurate interpretation of Raman spectra and their changes with respect to extrinsic and intrinsic defects requires a thorough assignment of the Raman modes to their respective crystal features, which to date is only partly conducted based on phenomenological modelling. To address this issue, we calculated the phonon spectra of potassium titanyl phosphate and the related compounds rubidium titanyl phosphate (RbTiOPO4) and potassium titanyl arsenate (KTiOAsO4) based on density functional theory and compared them with experimental data. Overall, this allows us to assign various spectral features to eigenmodes of lattice substructures with improved detail compared to previous assignments. Nevertheless, the analysis also shows that not all features of the spectra can unambigiously be explained yet. A possible explanation might be that defects or long range fields not included in the modeling play a crucial rule for the resulting Raman spectrum. In conclusion, this work provides an improved foundation into the vibrational properties in the KTiOPO4 material family.}},
author = {{Neufeld, Sergej and Gerstmann, Uwe and Padberg, Laura and Eigner, Christof and Berth, Gerhard and Silberhorn, Christine and Eng, Lukas M. and Schmidt, Wolf Gero and Rüsing, Michael}},
issn = {{2073-4352}},
journal = {{Crystals}},
number = {{10}},
publisher = {{MDPI AG}},
title = {{{Vibrational Properties of the Potassium Titanyl Phosphate Crystal Family}}},
doi = {{10.3390/cryst13101423}},
volume = {{13}},
year = {{2023}},
}
@article{54854,
abstract = {{Batteries based on heavier alkali ions are considered promising candidates to substitute for current Li-based technologies. In this theoretical study, we characterize the structural properties of a novel material, i.e., F-doped RbTiOPO4 (RbTiPO4F, RTP:F), and discuss aspects of its electrochemical performance in Rb-ion batteries (RIBs) using density functional theory (DFT). According to our calculations, RTP:F is expected to retain the so-called KTiOPO4 (KTP)-type structure, with lattice parameters of 13.236 Å, 6.616 Å, and 10.945 Å. Due to the doping with F, the crystal features eight extra electrons per unit cell, whereby each of these electrons is trapped by one of the surrounding Ti atoms in the cell. Notably, the ground state of the system corresponds to a ferromagnetic spin configuration (i.e., S=4). The deintercalation of Rb leads to the oxidation of the Ti atoms in the cell (i.e., from Ti3+ to Ti4+) and to reduced magnetic moments. The material promises interesting electrochemical properties for the cathode: rather high average voltages above 2.8 V and modest volume shrinkages below 13% even in the fully deintercalated case are predicted.}},
author = {{Bocchini, Adriana and Xie, Yingjie and Schmidt, Wolf Gero and Gerstmann, Uwe}},
issn = {{2073-4352}},
journal = {{Crystals}},
number = {{1}},
publisher = {{MDPI AG}},
title = {{{Structural and Electrochemical Properties of F-Doped RbTiOPO4 (RTP:F) Predicted from First Principles}}},
doi = {{10.3390/cryst14010005}},
volume = {{14}},
year = {{2023}},
}
@article{54853,
abstract = {{The nitrogen-vacancy (NV) centers (NCVSi)− in 4H silicon carbide (SiC) constitute an ensemble of spin S = 1 solid state qubits interacting with the surrounding 14N and 29Si nuclei. As quantum applications based on a polarization transfer from the electron spin to the nuclei require the knowledge of the electron–nuclear interaction parameters, we have used high-frequency (94 GHz) electron–nuclear double resonance spectroscopy combined with first-principles density functional theory to investigate the hyperfine and nuclear quadrupole interactions of the basal and axial NV centers. We observed that the four inequivalent NV configurations (hk, kh, hh, and kk) exhibit different electron–nuclear interaction parameters, suggesting that each NV center may act as a separate optically addressable qubit. Finally, we rationalized the observed differences in terms of distinctions in the local atomic structures of the NV configurations. Thus, our results provide the basic knowledge for an extension of quantum protocols involving the 14N nuclear spin.}},
author = {{Murzakhanov, F. F. and Sadovnikova, M. A. and Mamin, G. V. and Nagalyuk, S. S. and von Bardeleben, H. J. and Schmidt, Wolf Gero and Biktagirov, Timur and Gerstmann, Uwe and Soltamov, V. A.}},
issn = {{0021-8979}},
journal = {{Journal of Applied Physics}},
number = {{12}},
publisher = {{AIP Publishing}},
title = {{{14N Hyperfine and nuclear interactions of axial and basal NV centers in 4H-SiC: A high frequency (94 GHz) ENDOR study}}},
doi = {{10.1063/5.0170099}},
volume = {{134}},
year = {{2023}},
}
@article{54851,
abstract = {{Composites of different graphene oxide types, TiO2 materials, and especially synthetic routes influence the photocatalytic activity of the resulting material.}},
author = {{Rosenthal, Marta and Biktagirov, Timur and Schmidt, Wolf Gero and Wilhelm, René}},
issn = {{2044-4753}},
journal = {{Catalysis Science & Technology}},
number = {{15}},
pages = {{4367--4377}},
publisher = {{Royal Society of Chemistry (RSC)}},
title = {{{Synthesis of new graphene oxide/TiO2 and TiO2/SiO2 nanocomposites and their evaluation as photocatalysts}}},
doi = {{10.1039/d3cy00461a}},
volume = {{13}},
year = {{2023}},
}
@article{54850,
author = {{Meier, Lukas and Schmidt, Wolf Gero}},
issn = {{1932-7447}},
journal = {{The Journal of Physical Chemistry C}},
number = {{4}},
pages = {{1973--1980}},
publisher = {{American Chemical Society (ACS)}},
title = {{{Adsorption of Cyclic (Alkyl) (Amino) Carbenes on Monohydride Si(001) Surfaces: Interface Bonding and Electronic Properties}}},
doi = {{10.1021/acs.jpcc.2c07316}},
volume = {{127}},
year = {{2023}},
}
@article{43827,
abstract = {{A series of new organic donor–π–acceptor dyes incorporating a diquat moiety as a novel electron-acceptor unit have been synthesized and characterized. The analytical data were supported by DFT calculations. These dyes were explored in the aerobic thiocyanation of indoles and pyrroles. Here they showed a high photocatalytic activity under visible light, giving isolated yields of up to 97 %. In addition, the photocatalytic activity of standalone diquat and methyl viologen through formation of an electron donor acceptor complex is presented.}},
author = {{Meier, Armin and Badalov, Sabuhi and Biktagirov, Timur and Schmidt, Wolf Gero and Wilhelm, René}},
issn = {{0947-6539}},
journal = {{Chemistry – A European Journal}},
keywords = {{General Chemistry, Catalysis, Organic Chemistry}},
number = {{22}},
pages = {{ e202203541}},
publisher = {{Wiley}},
title = {{{Diquat Based Dyes: A New Class of Photoredox Catalysts and Their Use in Aerobic Thiocyanation}}},
doi = {{10.1002/chem.202203541}},
volume = {{ 29}},
year = {{2023}},
}
@inproceedings{61362,
abstract = {{We study the interaction of gray tracking and DC ionic conductivity in Potassium Titanyl Phosphate (KTiOPO4, KTP) and present a novel way to reduce conductivity via a potassium nitrate treatment improving the device quality.}},
author = {{Eigner, Christof and Padberg, Laura and Quiring, Viktor and Bocchini, Adriana and Santandrea, Matteo and Gerstmann, Uwe and Schmidt, Wolf Gero and Silberhorn, Christine}},
booktitle = {{CLEO 2023}},
publisher = {{Optica Publishing Group}},
title = {{{Potassium Titanyl Phosphate Material Engineering Boosting Integrated Optical Source Performance}}},
doi = {{10.1364/cleo_at.2023.jw2a.57}},
year = {{2023}},
}
@inbook{61360,
author = {{Hajduk, Andreas and Zare Pour, Mohammad Amin and Paszuk, Agnieszka and Guidat, Margot and Löw, Mario and Ullmann, Fabian and Moritz, Dominik C. and Hofmann, Jan P. and Krischok, Stefan and Runge, Erich and Schmidt, Wolf Gero and Jaegermann, Wolfram and May, Matthias M. and Hannappel, Thomas}},
booktitle = {{Encyclopedia of Solid-Liquid Interfaces}},
isbn = {{9780323856706}},
publisher = {{Elsevier}},
title = {{{(Photo-)electrochemical reactions on semiconductor surfaces, part B: III-V surfaces–atomic and electronic structure}}},
doi = {{10.1016/b978-0-323-85669-0.00113-6}},
year = {{2023}},
}
@article{54849,
abstract = {{The third‐order susceptibility of lithium niobate (LiNbO3) is calculated within a Berry‐phase formulation of the dynamical polarization based on the electronic structure obtained within density‐functional theory (DFT). Maximum values of the order of m V are calculated for photon energies between 1.2 and 2 eV, i.e., in the lower half of the optical bandgap of lithium niobate. Both free and bound electron (bi)polarons are found to lead to a remarkable enhancement of the third‐order susceptibility for photon energies below 1 eV.}},
author = {{Kozub, Agnieszka L. and Gerstmann, Uwe and Schmidt, Wolf Gero}},
issn = {{0370-1972}},
journal = {{physica status solidi (b)}},
number = {{2}},
publisher = {{Wiley}},
title = {{{Third‐Order Susceptibility of Lithium Niobate: Influence of Polarons and Bipolarons}}},
doi = {{10.1002/pssb.202200453}},
volume = {{260}},
year = {{2022}},
}
@article{37711,
abstract = {{AbstractPolarons influence decisively the performance of lithium niobate for optical applications. In this work, the formation of (defect) bound polarons in lithium niobate is studied by ab initio molecular dynamics. The calculations show a broad scatter of polaron formation times. Rising temperature increases the share of trajectories with long formation times, which leads to an overall increase of the average formation time with temperature. However, even at elevated temperatures, the average formation time does not exceed the value of 100 femtoseconds, i.e., a value close to the time measured for free, i.e., self-trapped polarons. Analyzing individual trajectories, it is found that the time required for the structural relaxation of the polarons depends sensitively on the excitation of the lithium niobate high-frequency phonon modes and their phase relation.}},
author = {{Krenz, Marvin and Gerstmann, Uwe and Schmidt, Wolf Gero}},
issn = {{0947-8396}},
journal = {{Applied Physics A}},
keywords = {{General Materials Science, General Chemistry}},
pages = {{480}},
publisher = {{Springer Science and Business Media LLC}},
title = {{{Bound polaron formation in lithium niobate from ab initio molecular dynamics}}},
doi = {{10.1007/s00339-022-05577-y}},
volume = {{128}},
year = {{2022}},
}
@article{33484,
abstract = {{We study the DC conductivity in potassium titanyl phosphate (KTiOPO4, KTP) and its isomorphs KTiOAsO4 (KTA) and Rb1%K99%TiOPO4 (RKTP) and introduce a method by which to reduce the overall ionic conductivity in KTP by a potassium nitrate treatment. Furthermore, we create so-called gray tracking in KTP and investigate the ionic conductivity in theses areas. A local unintended reduction of the ionic conductivity is observed in the gray-tracked regions, which also induce additional optical absorption in the material. We show that a thermal treatment in an oxygen-rich atmosphere removes the gray tracking and brings the ionic conductivity as well as the optical transmission back to the original level. These studies can help to choose the best material and treatment for specific applications.}},
author = {{Padberg, Laura and Quiring, Viktor and Bocchini, Adriana and Santandrea, Matteo and Gerstmann, Uwe and Schmidt, Wolf Gero and Silberhorn, Christine and Eigner, Christof}},
issn = {{2073-4352}},
journal = {{Crystals}},
pages = {{1359}},
title = {{{DC Ionic Conductivity in KTP and Its Isomorphs: Properties, Methods for Suppression, and Its Connection to Gray Tracking}}},
doi = {{10.3390/cryst12101359}},
volume = {{12}},
year = {{2022}},
}
@article{26627,
abstract = {{Many-body perturbation theory based on density-functional theory calculations is used to determine the quasiparticle band structures and the dielectric functions of the isomorphic ferroelectrics rubidium titanyl phosphate (RbTiOPO4) and potassium titanyl arsenide (KTiOAsO4). Self-energy corrections of more than 2 eV are found to widen the transport band gaps of both materials considerably to 5.3 and 5.2 eV, respectively. At the same time, both materials are characterized by strong exciton binding energies of 1.4 and 1.5 eV, respectively. The solution of the Bethe-Salpeter equation based on the quasiparticle energies results in onsets of the optical absorption within the range of the measured data.}},
author = {{Neufeld, Sergej and Schindlmayr, Arno and Schmidt, Wolf Gero}},
issn = {{2515-7639}},
journal = {{Journal of Physics: Materials}},
number = {{1}},
publisher = {{IOP Publishing}},
title = {{{Quasiparticle energies and optical response of RbTiOPO4 and KTiOAsO4}}},
doi = {{10.1088/2515-7639/ac3384}},
volume = {{5}},
year = {{2022}},
}
@article{37656,
author = {{Glahn, Luis Joel and Ruiz Alvarado, Isaac Azahel and Neufeld, Sergej and Zare Pour, Mohammad Amin and Paszuk, Agnieszka and Ostheimer, David and Shekarabi, Sahar and Romanyuk, Oleksandr and Moritz, Dominik Christian and Hofmann, Jan Philipp and Jaegermann, Wolfram and Hannappel, Thomas and Schmidt, Wolf Gero}},
issn = {{0370-1972}},
journal = {{physica status solidi (b)}},
keywords = {{Condensed Matter Physics, Electronic, Optical and Magnetic Materials}},
number = {{11}},
publisher = {{Wiley}},
title = {{{Clean and Hydrogen‐Adsorbed AlInP(001) Surfaces: Structures and Electronic Properties}}},
doi = {{10.1002/pssb.202200308}},
volume = {{259}},
year = {{2022}},
}
@article{37710,
author = {{Ruiz Alvarado, Isaac Azahel and Schmidt, Wolf Gero}},
issn = {{2470-1343}},
journal = {{ACS Omega}},
keywords = {{General Chemical Engineering, General Chemistry}},
number = {{23}},
pages = {{19355--19364}},
publisher = {{American Chemical Society (ACS)}},
title = {{{Water/InP(001) from Density Functional Theory}}},
doi = {{10.1021/acsomega.2c00948}},
volume = {{7}},
year = {{2022}},
}
@article{37681,
author = {{Moritz, Dominik Christian and Ruiz Alvarado, Isaac Azahel and Zare Pour, Mohammad Amin and Paszuk, Agnieszka and Frieß, Tilo and Runge, Erich and Hofmann, Jan P. and Hannappel, Thomas and Schmidt, Wolf Gero and Jaegermann, Wolfram}},
issn = {{1944-8244}},
journal = {{ACS Applied Materials & Interfaces}},
keywords = {{General Materials Science}},
number = {{41}},
pages = {{47255--47261}},
publisher = {{American Chemical Society (ACS)}},
title = {{{P-Terminated InP (001) Surfaces: Surface Band Bending and Reactivity to Water}}},
doi = {{10.1021/acsami.2c13352}},
volume = {{14}},
year = {{2022}},
}
@article{37714,
author = {{Karmo, Marsel and Ruiz Alvarado, Isaac Azahel and Schmidt, Wolf Gero and Runge, Erich}},
issn = {{2470-1343}},
journal = {{ACS Omega}},
keywords = {{General Chemical Engineering, General Chemistry}},
number = {{6}},
pages = {{5064--5068}},
publisher = {{American Chemical Society (ACS)}},
title = {{{Reconstructions of the As-Terminated GaAs(001) Surface Exposed to Atomic Hydrogen}}},
doi = {{10.1021/acsomega.1c06019}},
volume = {{7}},
year = {{2022}},
}
@article{33965,
author = {{Bocchini, Adriana and Gerstmann, Uwe and Bartley, Tim and Steinrück, Hans-Georg and Henkel, Gerald and Schmidt, Wolf Gero}},
journal = {{Phys. Rev. Materials}},
pages = {{105401}},
publisher = {{American Physical Society}},
title = {{{Electrochemical performance of KTiOAsO_4 (KTA) in potassium-ion batteries from density-functional theory}}},
doi = {{10.1103/PhysRevMaterials.6.105401}},
volume = {{6}},
year = {{2022}},
}
@article{31254,
author = {{Bocchini, Adriana and Gerstmann, Uwe and Schmidt, Wolf Gero}},
journal = {{Phys. Rev. B}},
pages = {{205118}},
publisher = {{American Physical Society}},
title = {{{Oxygen vacancies in KTiOPO_4: Optical absorption from hybrid DFT}}},
doi = {{10.1103/PhysRevB.105.205118}},
volume = {{105}},
year = {{2022}},
}